The present invention relates to the portable power source industry and, more particularly, to the field of portable power sources for providing supplemental power to electrical and mechanical systems.
The need for a portable power source arises frequently in a variety of circumstances. Among the most common of circumstances is the situation in which a commercial or family vehicle fails to start because of a xe2x80x9cdeadxe2x80x9d battery. A commercial or family vehicles typically is powered by a conventional internal combustion engine which requires a separate electric motor (i.e., xe2x80x9cstarterxe2x80x9d) that rotates the engine crankshaft at a speed sufficient to start the engine. Because the starter is electrically powered by an automobile battery, if the battery goes dead or otherwise loses a substantial amount of stored energy when the vehicle""s lights or radio are left on while the engine is off, then the engine will not start. This phenomenon has existed since the introduction of the electric starter and lead acid storage battery on a vehicle, and it is especially prevalent during cold weather when vehicles are generally more difficult to start and extra engine-off loads are left on (e.g., electrical heaters) causing the vehicle""s battery to discharge even faster.
In such circumstances, it is necessary to have the benefit of a supplemental source of power to xe2x80x9cjump startxe2x80x9d the vehicle""s engine. With a jump start, because the vehicle battery does not have the needed energy or electrical xe2x80x9cpushxe2x80x9d (i.e., voltage) necessary, supplementary power is applied to the electrical system or starter motors. Jump starts typically have been applied two ways: (1) application of additional battery power in parallel with the existing battery or batteries on the vehicle or machinery; and (2) generation of direct current power produced by a generator or alternator driven by a separate engine.
Thus, with respect to the first method of providing a jump start, most conventional devices still continue to rely on a direct current power source provided by a battery. Recent examples of such devices are U.S. Pat. No. 6,130,519 to Whiting et al. titled Portable Battery Charger Including Auto-Polarity Switch and U.S. Pat. No. 5,793,185 to Prelec et al. titled Jump Starter, which describe power booster devices using a battery. The jump start is performed with the application of extra battery power in parallel with the existing battery on a vehicle and requires that connecting leads, or xe2x80x9cjumper cables,xe2x80x9d be connected from an external power source, conventionally a separate battery, to the battery on the vehicle. With this method of jump starting, the separate, charged battery provides extra energy to the disabled battery of the vehicle and thus may enable the engine starting operation. In essence, the extra battery is temporarily boosting the voltage, and thus, the available power in the system, so that the starter motor may have sufficient energy to start the engine; that is, this momentary boost in electrical energy to the starter motor may be sufficient to start the engine if the supplemental battery provides sufficient power.
Unfortunately, the supplemental battery does not always provide sufficient power. The amount of power required by the supplemental battery is a function of many factors, including the size of the engine to be started, its temperature, oil, and viscosity, as well as the remaining energy of the disabled vehicle battery. The supplemental battery must provide enough additional energy to equal the normal level of power available from a fully charged battery installed in the vehicle. If, for example, the vehicle battery is completely discharged, the supplemental battery may not have sufficient energy to make the starter motor function properly. Some devices have sought to boost the energy supplied by a supplementary battery used to recharge a disabled battery. U.S. Pat. No. 5,637,978 to Kellett et al. titled Battery Booster, for example, describes a xe2x80x9cboost converterxe2x80x9d comprising a switch, diode and inductor to step up the primary power supplied by a battery. Depending on the above-described conditions, however, the additional 2 to 3 volts provided may not be sufficient, especially in attempting to start the heavy engine of a large-sized heavy-duty commercial vehicle. U.S. Pat. No. 4,510,431 to Winkler titled D.C. Stepped-Up Voltage Transfomerless Battery Charger, steps up the voltage of a direct current battery by applying a supplementary source power via alternating current to a capacitor. While this may be useful for recharging batteries in hand-held devices (e.g., walkie-talkies or radios), it may not be suitable for recharging vehicle batteries stranded away from a source of alternating current and requiring a much greater supplementary power.
Moreover, conventional devices, because of the limited amount of supplementary power delivered in a single, short burst, frequently require significant time durations to recharge the vehicle battery. The level of discharge of the existing vehicle battery, as noted, will determine at least partly the time necessary to recharge a disabled battery, or even whether the vehicle can be jump-started at all. If the supplementary battery power has insufficient power itself, the discharged battery may require significant time to receive the energy flow needed so that it can work with the supplementary battery to start the engine. At lower temperatures for example, the energy flow becomes slower. When temperature is low the chemical properties of a conventional battery do not allow the battery to function as well in any charge condition, but especially when it is severely discharged. If severely discharged, then the vehicle battery may take a significant amount of time to recharge.
Conventional techniques pose other problems as well. Initially, when batteries are connected in parallel, the discharged battery begins to draw energy from the charged battery. If left in a steady state, the discharged battery will eventually drain energy from the charged battery to the point where the combination of the parallel batteries will reach equilibrium with equal electrical energy in each.
Conventional techniques also can create other potential problems as well. Sparks can be generated when the supplementary battery is electrically connected to the existing vehicle battery. If the battery is connected improperly, the likelihood of sparks increases. There is also potential damage to both the vehicle battery and the vehicle electrical system. Gases produced by the battery can be ignited causing explosion and bodily harm to the installer along with damage to the vehicle.
Providing a power boost can alternatively be accomplished by generation of direct current power produced by generators or alternators that are driven by some type of engine. As with providing a supplementary battery to boost power, in order for a standby power generation unit to be effective, it needs the capability to produce sufficient power to either activate the starting motor independently or it must supplement the existing vehicle battery as already described above. It is generally not practical, due to size and cost, to have a generator set large enough to turn the engine by itself. Therefore, a jump start using this method is normally accomplished by boosting output voltage of the generator set beyond normal operating levels in order to charge the existing vehicle battery.
This increased voltage, however, leads to its own set of potential problems. The voltage levels produced are conventionally controlled either manually or by built in voltage regulators. When set manually, an operator must monitor the output of the unit and the charging process. The charging process takes time as described above. This requires that the operator devote full attention to the process. It is costly, though, for an operator to simply watch the unit perform. If the unit performs out of control, however, damage will be caused to the batteries and potentially to the starter motor and electrical system of the vehicle. If the unit is left completely unattended, the voltage can climb to an unsafe level and explosion can occur causing damage to the battery, generator set, vehicle electrical system, and potentially bodily harm to persons within the vicinity of the vehicle. The least of the problems that will result from overcharge is shortened life from the vehicle battery.
If the unit is controlled by built-in voltage regulators, they can and often do fail. Calibrations are seldom checked. Regulators are seldom serviced. Therefore, even in an automatic mode, potential runaway overcharge can and often does occur.
In either mode of supplying supplementary power, the engine that drives the generator set must have fuel. If the unit is operating unattended, the engine can run out of fuel at an inopportune time. At this point, the generators attempt to reverse action. They start drawing energy from the battery which was formerly being charged as the generator attempts to function as a starter motor to turn the engine which is normally its driver. The result is that the battery is again discharged. In summary, the operation of a standby generator set is costly with operator in attendance, but very dangerous without operator in attendance.
In view of the foregoing background, the present invention advantageously provides an apparatus and method for delivering supplemental power to the electrical system of a vehicle or other machinery. The advantages afforded by the claimed invention and described herein provide particular benefits in boosting power in the electrical system of a vehicle disabled by a discharged battery. The claimed invention provides a power source with the capability to convey concentrated, rapid-delivery power to an electrical system, while automatically controlling the extent and timing of power delivery so as to deliver an optimal amount of power without risk of overloading the electrical system being boosted.
Specifically, the claimed invention utilizes an electronically controlled power booster combination of high-density capacitor and battery. The capacitor, as described in detail below, is capable of storing a tremendous amount of charge and is thereby able to provide, via rapid transference of concentrated energy, a substantial power boost to an electrical system. As further described below, the claimed invention utilizes a capacitor-battery combination that includes an electrochemical capacitor, which depending on its particular construction can contribute to the storage of tremendous amounts of charge. The energy level of the capacitor is sustained at or above a preselected minimum level by the electrically connected battery.
An apparent offset to the advantages associated with rapid-burst, high-concentration power delivery, however, is that too much power may be delivered too quickly to the electrical system or before an improper connection between the power booster and electrical system has been detected. The present invention overcomes this problem by providing a power delivery controller having electronic circuitry that optimally controls power delivery as alluded to above. Specifically, the power delivery controller includes voltage detecting capabilities to detect voltage conditions in the electrical system to receive a power boost and an isolation circuit responsive to the detected voltage conditions to optimally control power delivery. More specifically, the voltage conditions indicate when a proper connection between the power source and the electrical system has been established, when power is to be supplied from the power source, and when an optimal amount of power has been delivered to the electrical system from the power source. These capabilities, thus, work jointly to determine when the proper conditions for power delivery exist, then respond by permitting power delivery from a power booster source to the electrical system, and finally block power delivery as soon as the optimal amount of power has been delivered.
In the specific context of starting a vehicle disabled by a discharged battery, the invention determines whether a power source connection has been properly made between a power source and the vehicle battery. If so, it allows the power source to rapidly deliver concentrated power to the vehicle from the power source comprising a combination capacitor (preferably an electrochemical type) and battery. The concentrated power is delivered directly to the vehicle""s alternator and engine in sufficient amounts to start the vehicle engine without having to rely on the vehicle""s discharged battery for power. When the vehicle engine starts, the vehicle""s engine begins to recharge the discharged vehicle battery, and the electronically controlled isolation circuit blocks further power delivery from the power source. Only power enough to turn the alternator and start the vehicle""s engine is delivered from the power source and no more, thereby avoiding risk of providing too much power too quickly.
Continuing in the context of providing a power boost to a disabled vehicle, a further advantage of the present invention is the ability to replenish the capacitor using the very vehicle which has been started in the manner just described. As noted, the electronically controlled isolation circuit blocks further power delivery from the power source as soon as the engine of the disabled vehicle has been started. The power connection between the vehicle and the power source is maintained, though, according to the present invention, so that as the now-started vehicle engine begins to recharge the vehicle battery it also delivers energy to the capacitor. The result is that power that was delivered from the power source to start the vehicle is now returned to the power source to be stored by the power source capacitor. In this sense, the invention provides a sustainable source of power for boosting an electrical system.
Again, in the context of boosting the disabled battery of a heavy-duty vehicle, sufficient energy is provided by a power source combining a high-density capacitor and battery as to turn a large engine to thereby efficiently and rapidly start the vehicle. Thus, the claimed invention""s ability to provide a rapid-delivery, concentrated power boost is uniquely suited to recharging disabled batteries on large commercial transport vehicles quickly and efficiently. The claimed invention""s ability to provide substantial power boosts, in contrast to the generators and similar devices earlier described, is not at the expense of a large and cumbersome construction; the claimed invention is highly portable. It can be lifted by hand onto a vehicle or cart for long distance transport and thus, the claimed invention""s ability to provide a portable power boost is uniquely suited to recharging disabled batteries on large commercial transport vehicles stranded in remote areas. This combination of rapid, high power delivery and portability provides considerable advantages over conventional charging devices and methods.
As described, although designed to deliver high levels of power, the claimed invention also possesses unique features that match voltages so as to avoid damage to the electrical system during power transfers and control where dispensed energy is delivered. Specifically, the claimed invention has a control capacity to determine the voltage requirements of the electrical system. It also isolates the source of power from the electrical system until a proper power delivery connection is made so as to avoid inadvertent discharge or overvoltages owing to improper hook-up between the power source and the electrical system. There is, thus, a built-in reverse polarity protection. Relatedly, there is same polarity protection in the sense that an accidental connection of power source conductors to the same terminal of the electrical system battery causing a direct short will be xe2x80x9csensedxe2x80x9d before power delivery is initiated, thereby reducing risk of damage to the invention and the electrical system.
The claimed invention achieves these advantages, as already noted, by providing a combination voltage detecting or sensing circuit working jointly with an isolation circuit that prevents delivery of power from the invention""s power source unless the proper voltage determinations are made. In one specific embodiment of the invention, a manually actuated switch prevents any current exchange until the operator has connected the power booster and the electrical system and is safely situated to remotely control power delivery. Even after the switch is actuated, the sensing circuit operates to detect whether the proper voltages exist at power supply connection (i.e., a 0.7V voltage across the terminals of a disabled battery). If not, the isolation circuit, which can be an arrangement of magnetic switches, prevents any electrical current to pass between the power source and the electrical system. If a proper connection has been made, the capacitor-battery combination power source delivers through the power supply connection a high concentration of power.
In an alternative embodiment, the voltage detection circuit and isolation circuit include a processor and timer. The voltage within the electrical system is detected after the connection is made between the power booster and the electrical system. The process further includes a register to store a numerical indicator of the initial voltage detected. If a subsequent drop in voltage is detected (expected to be approximately a 2V drop in voltage), the processor signals the isolation circuit to permit current-borne delivery of power. In conjunction with the timer, then, the processor compares subsequent voltage with the initial voltage and determines whether an expected rise in voltage has occurred within a prescribed time interval (expected to be approximately a 1.5V rise in voltage within approximately 10 seconds). If so, then the processor signals the isolation circuit to permit continued passage of current for a second prescribed time interval, during which the electrical system will be sufficiently recharged and current will reverse so that the power source can be recharged by the now-enabled electrical system. If the expected rise in voltage does not occur within the first time interval, however, the isolation circuit operates to block any further current passing because of an incorrect connection or inherent problems in the electrical system itself.
These alternative embodiments, with varying degrees in cost of manufacture and of efficiency for the operator, each provide the capabilities alluded to earlier regarding the avoidance of overvoltage (with the corresponding risks of sparking), shorts, and damaging polarity reversals. Specifically, the ability, automatically and manually, to electrically isolate the power source and the electrical system during the process of making a power delivery connection avoids risks of sparking when connecting and disconnecting the separate conductors. These alternative embodiments also provide reverse polarity protection in that if an improper hook-up is made, the power booster avoids delivery of power thereby reducing the risk that the electrical system or booster will be damaged. Similarly, there is same-polarity protection in that if a short condition is created by improperly connecting both power booster conductors to the same terminal of the electrical system, no power delivery will be initiated, thereby reducing the risk that the electrical system or booster will be damaged.
It is further envisioned that the same voltage sensing circuitry and associated isolation circuits would have other applications in the context of electrical starting systems for vehicle engines using capacitors in lieu of or in conjunction with conventional starter batteries. The U.S. Army, for example has experimented with starting systems comprising only two batteries and a capacitor for use with the diesel engines for five- and seven-ton vehicles. See, e.g., J. R. Miller, J. Burgel, H. Catherino, F. Drestik, J. Monroe and J. R. Stafford, Truck Starting Using Electrochemical Capacitors (1998). Such vehicles are difficult to start (especially at low temperatures) and normally require four batteries for starting, which necessitates frequent and costly battery replacements. Use of such alternative systems was pioneered more than a decade ago by the Russian military and is expected to become increasingly more common in many vehicles in the years ahead. One additional advantageous use, then, of the sensing circuitry and associated isolation circuits of the present invention, would be to provide monitoring within such a system to detect a malfunctioning alternator or other impediment to starting the engine that does not result from a discharged capacitor or battery. Failure to start the engine owing to reasons having nothing to do with a discharged battery or capacitor are important to detect, and the earlier, the better. Doing so can avoid unnecessary dissipation of the capacitor and/or battery as when power is drained from the system by an internal system fault or by vainly trying to start the engine disabled by a faulty electrical system. Detection can also avoid potentially damaging attempts to boost the capacitor or battery when in fact the failure to start is due to some inherent problem in the electrical system.
Yet a further advantage of the present invention is the ability to perform multiple power boosts, or xe2x80x9cjump starts,xe2x80x9d between recharging of the power source. Indeed, under normal operating circumstances, it is expected that the claimed invention will provide at least 10 times, and likely many more, the number of power boosts than conventional devices and methods currently provide. The high-density capacitor is maintained by the connected batter. Moreover, as earlier described, after the invention recharges an electrical system, the electrical system can return a replenishing charge to the high-energy/battery combination. The purposefully selected low internal resistance of the capacitor, moreover, enhances the capacitor""s capability to accept the recharge current from even a small or nearly discharged battery. This lower resistance further enables the capacitor to be rapidly recharged, as for example by a jump started vehicle alternator. Under normal circumstances, recharging can take less than a minute. These features, therefore, allow the capacitor to maintain sufficient voltage to provide enumerable power boosts over virtually any span of time.
The advantages provided by this recharge capability are further enhanced by the ability of the present invention to accept energy via either alternative current or direct current. Thus, the invention is adapted to include a conventional wall-plug to plug into a 110 volt wall socket to be recharged by conventional alternating current supplied to homes and businesses. At the same time, the invention is adapted to connect to a conventional 12 volt battery for recharging as well. Thus, for example, the invention can be recharged by a vehicle battery as the invention is being transported on the vehicle to a remote site where it is to be employed to boost the discharged battery of a stranded vehicle, thereby further supplementing the invention""s advantage relative to conventional devices and methods.